Re: missing support for db _PROPERTY columns ?

From: Andrus Adamchik (andru..bjectstyle.org)
Date: Fri Apr 23 2004 - 11:05:35 EDT

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    [... Taking this to cayenne-user list, since it really belongs there...]

    Hi Matt,

    just like Mike said, if you need to reference related objects in
    qualifier, just use relationships. This is no different from EOF:

    DataObject relatedObject...;
    Expression qualifier = ExpressionFactory.matchExp("toRelatedObject",
    relatedObject);
    List objects = context.performQuery(new SelectQuery(MyClass.class,
    qualifier);

    No FK involved.

    Andrus

    On Apr 23, 2004, at 10:46 AM, Mike Kienenberger wrote:

    > Matt Kerr <mat..entralparksoftware.com> wrote:
    >> i have a situation (for better or worse)
    >> where i'm querying the database against an fk value.
    >> it's only a problem because i have a relationship built on top of that
    >> fk column.
    >>
    >> it seems like although cayenne is aware of the fk columns,
    >> it's not completely supporting them - ?
    >>
    >> i would like to reference the fk by _PROPERTY name when building the
    >> qualifier/expression -
    >> and i end up adding this to my impl :-( ...
    >
    > Querying by a foreign key value is like querying by a primary key
    > value. It
    > can be done, but it's not encouraged. Instead, you should just be
    > following the relationship.
    >
    > If you have a Contact record with an Address fk, you should be using
    > aContact.getAddress() to look up the address record.
    >
    > If you're just looking up arbitrary Address records, it's not a
    > foreign key
    > issue, it's a primary key issue for the Address table.
    >



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